Armature structure for an electromagnetic device



Sept. 5, 1967 w. GRUNER ETAL 3,340,487

' ARMATURE STRUCTURE FOR AN ELECTROMAGNETIC DEVICE Original Filed April 21, 1965 2 5heets-Sheet 1 INVENTORS Wolfgang GRUNER Hans SAUER MA! (W00 W WWW/0% Se t. 5, 1967 w. GRUNER ETAL 3,340,437

ARMATURE STRUCTURE FOR AN ELECTROMAGNETIC DEVICE Original Filed April 21, 1965 f I I M INVENTORS Wolfgang GRUNER Hans SAUER 2 Sheets-Sheet Z; Y

G 17 Claims. (Cl. 335-203) This application is a continuation of SN. 449,806 filed Apr. 21, 1965, and now abandoned.

This invention relates to electromagnetic apparatus such as, for example, electromagnetic relays. More paricularly, the invention relates to a novel, highly efficient electromagnetic circuit structure including a movable armature, and in which the attractive force exerted on the armature varies as a function of the operating path thereof.

An electromagnetic device must include at least an energizing winding, a ferromagnetic circuit, and one or more air gaps. The ferromagnetic circuit usually comprises a core, a yoke and a movably mounted armature. There are numerous forms of electromagnetic devices, such as relays, and in the known forms the magnetic cir cuit may include either a single air gap or two effective air gaps. Arrangements including two effective air gaps have the advantage, over arrangements having a single air gap, that once the magnetic flux is produced, it has an almost double effect with a small path of movement of the armature.

Other arrangements are known, among these being the so-called hinged armature electromagnetic devices which include a two-part armature. One part of this armature, together with the core, forms a ferromagnetic material magnetic circuit including an air gap. The other part of the armature, which serves to operate electrical contacts, spring arrangements, etc., comprises diamagnetic material such as, for example, brass. By such atwo-part arrangement, there is avoided the possibility that a part of the magnetic flux can exert a magnetic force acting on the armature in opposition to the direction of attraction. Arrangements of this latter type are relatively expensive due to the two-part construction of the armature.

An object of the present invention is to provide an electromagnetic structure which is at least as effective as one including a two-part armature but which avoids the expense inherent upon the two-part armature type of structure.

Another object of the invention is to provide an electromagnetic structure having an armature including an operating arm, and utilizing the magnetic flux between the yoke and the operating arm in the direction of attraction of the armature.

A further object of the invention is to provide an electromagnetic structure including an armature having an operating arm, and utilizing the magnetic flux between the yoke and the operating arm in the direction of attraction, but in which the attraction characteristic between the operating arm and the yoke differs, for purposes of compensation, from the attraction across the air gap between the armature per se and the core.

Yet another object of the invention is to provide an electromagnetic structure including a core and an armature having an operating arm, and characterized by compactness by positioning the operating arm inside a yoke whereby the yoke may be provided with a leg which can be used as a mounting means.

. For an understanding of the principles of the inven- United States Patent tion, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is an elevation view of one form of electromagnetic structure embodying the invention;

FIGS. 2 and 3 are vertical sectional views, taken on the line II of FIG. 1, illustrating two different arrangements of the parts of the structure shown in FIG. 1;

FIG. 4 is a graph illustrating the variation in magnetic attractive force, with variations in effective spacing or effective air gap, operating on an armature;

FIG. 5 is a vertical sectional view, taken on the line V of FIG. 7, of an electromagnetic relay embodying the invention;

FIG. 6 is a vertical sectional view, taken on the line IV of FIG. 5;

FIG. 7 is a top plan view of the relay shown in FIGS. 5 and 6, looking in the direction of the arrow W of FIG. 5;

FIG. 8 is a horizontal sectional view taken on the line VIII of FIG. 6;

FIG. 9 is a sectional View, taken on the line IX of FIG. 10; and

FIG. 10 is a partial elevational view, taken in the direction of the arrow Z of FIG. 5.

Referring first to the electromagnetic structure illustrated in FIGS. 1, 2 and 3, this structure includes a paramagnetic, which means the same as ferromagnetic in this application, material armature 1 having operating legs 2 and 3 extending substantially at right angles thereto, the armature 1 bridging the legs 5 and 6 of a generally U-shape paramagnetic material yoke on which is supported a paramagnetic material core 4 operatively associated with the armature 1 and provided with an energizing winding 13. Armature 1 is oscillatably supported upon the yoke legs 5 and 6 in a manner described more fully hereinafter.

The magnetic yoke has a third or central leg 7 which lies in a plane perpendicular to the planes of the yoke legs 5 and 6. Leg 7, which is preferably used to mount the components associated with the electromagnetic structure, has two laterally extending shoulders 10 and 11. Adjacent these shoulders there are lugs 8 and 9 on the ends of the armature arms 2 and 3, respectively. The space between shoulders 10, 11 and armature lugs 8, 9 provides a relatively large operating path with an additional air gap which thus is arranged, by preference, far from the fulcrum of armature 1 in order to obtain the highest torque possible. The relation of the force P to the travel S resulting from this air gap is illustrated graphically by the curve 0 in FIG. 4. From FIG. 4, it will be noted that curve 0 is similar to that of a so-called immersion magnet system, and the greatest attractive force P is effective shortly before the immersion. This position corresponds approximately to the position of the armature lug 8 as illustrated in FIG. 2. It can readily be noted that the position of armature lug 8 is, to a large extent, independent of the air gap 1.

An important feature of the present invention is that the force-travel characteristic of a hinged or oscilla-table armature system cooperates, in the electromagnetic structure, with the force-travel characteristic of an immersion magnetic system. Thus, the steep force-travel characteristic resulting from the attraction between armature 1 and core 4, as well as the steep force-travel characteristic resulting from the attraction between the armature 1 and yoke legs 5 and 6, is increased by an additional attractive force P which has its maximum value when the armature is open.

Curve b of FIG. 4 is the force-travel characteristic of the combined system, just mentioned, and may be compared with curve a which represents the force-travel characteristic without the additional attraction component due to the attraction force P. It will be noted that the attractive force represented by curve b is in opposition to the attractive force represented by curve a only if, as shown in FIG. 3, armature lug 8 is in the position 8 shown in broken lines, and thus there is exerted on armature 1 a counter-torque compared to the attractive forces. Such a position 8' of armature lug 8 is particularly desirable when the magnetic system is to be used in relay having extreme drop-in conditions, or if it is required that the attraction of the armature be damped in the end phase.

FIGS. -10 illustrate the magnetic structure of FIGS. 1, 2 and 3 as incorporated in an electromagnetic relay. -In the relay shown, in FIGS. 5-10, the magnetic structure is inverted as compared to its illustration in FIGS. 1, 2 and 3. In FIGS. 5-8, the relay is shown in the energized position with armature 1 closed and with closed or transferred contacts 26, 27. In FIGS. 9 and the armature is illustrated in the open position.

The illustrated relay includes a base 24 which preferably is made of dielectric material and has an upwardly extending arm 25. Arm 25 extends between the electrical contact assembly 28 and the leg 7 of the magnetic yoke, this leg 7 having a threaded aperture (FIG. 1) to receive the threaded end of a mounting screw 29 which extends through contact assembly 28 and arm .25. Contacts 27 are provided with operating fingers or the like 31, of dielectric material, which engage armature arms 8 and 9 for the purpose of operating contacts 26 and 27, which latter are normally open.

The relay further includes the magnetic core 4, the bobbin or spool 32 on which is wound the relay winding 13, and the terminals 33 and 34 for the relay Winding, all of which are mounted and connected in a conventional manner.

The inside of the bend of armature 1 is formed with a pair of triangular cross section fillets which engage the heads of yokes 5 and 6, respectively, and thus maintain armature I1 against lateral displacement relative to the magnetic yokes. A spring 18 is secured on yoke leg 7 by means of a screw or stud 30, and has arms 16 and 17 extending downwardly adjacent either edge thereof, as best seen in FIGS. 5, 6, 9 and 1 0. These springs engage the outer surface of the bend in armature 1 and thus bias armature 1 into pivoting engagement with bearing edges 19 and 20 on the heads of yoke parts or legs 5 and 6.

Spring 18 has a third arm 21, which is adjustable and which extends upwardly therefrom as viewed in FIG. 6, and this determines the travel S of armature arms 8 and 9. This spring, as best seen in FIGS. 6 and 8, has an end offset inwardly and then bent over to extend behind legs 8 and 9. Another spring 22 is secured with the mounting screw 23 of base 24, and acts on armature 1 at a distance a from bearing edges 19 and 20 in order to reset the armature into the rest position when the relay is deenergized.

It should be emphasized that there are three working air gaps in the magnetic structure. These are: (l) the air gap l between the arms 5 and 6 of the magnetic yoke, (2) the air gap 1 between armature 1 and core 4, (3) the air gaps between armature arms 8, 9 and shoulders 10, 11, respectively, of the magnetic yoke. Furthermore, the air gap between the armature legs 8, 9 and the yoke shoulders 10, 11 has a force-travel characteristic different from that of the air gaps between armature 1 and core 4 or between armature 1 and legs 5, 6 of the magnetic yoke.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it should be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. An electromagnetic structure comprising, in combination, a paramagnetic material yoke; a paramagnetic material core in magnetic circuit with said yoke; said yoke having leg means extending from one pole of said core in spaced parallel relation to said core and terminating in the plane of the opposite pole of said core in laterally spaced relation with said pole; and a paramagnetic material armature oscillatably supported at said leg means and forming, with said opposite pole of said core and 'with said leg means, first and second air gaps; said armature having an arm extending substantially parallel to said core and having a free end forming, with said leg means, an air gap augmenting the magnetic attraction effect on said armature.

2. An electromagnetic structure, as claimed in claim 1, in which said yoke includes another leg extending from said one pole of said core in substantially parallel spaced relation to said core and laterally spaced from said leg means; said armature arm forming, with said other leg of said yoke, an air gap augmenting the magnetic attraction effect on said armature.

3. An electromagnetic structure, as claimed in claim 1, in which said leg means comprises a pair of laterally spaced legs terminating at free ends substantially in the plane of the opposite pole of said core; said armature being oscillatably supported at said free ends of said legs and forming, with said opposite pole of said core and with said free leg ends, first and second air gaps; the free end of said armature arm forming, with said legs, an air gap augmenting the magnetic attraction effective on said armature.

4. An electromagnetic structure, as claimed in claim 2, in which said leg means comprises a pair of laterally spaced legs terminating at free ends substantially in the plane of the opposite pole of said core; said paramagnetic material armature being oscillatably supported at said free ends of said legs; said other leg constituting a third leg of said yoke.

5. An electromagnetic structure, as claimed in claim 4, in which said third leg has a lug extending laterally therefrom in alignment with the free end of said arm; said last-named air gap being formed between said third leg and the free end of said arm.

6. An electromagnetic structure, as claimed in claim 4, in which said arm is adjustable with respect to said third yoke leg.

7. An electromagnetic structure, as claimed in claim 4, in which said armature arm extends in laterally adjacent relation to a side edge of said third leg and forms, with said third leg, said last-mentioned air gap.

8. An electromagnetic structure, as claimed in claim 2, in which said armature has a pair of laterally spaced arms extending substantially parallel to said core in laterally spaced relation to opposite side edges of said other leg, and forming, with said other leg, air gaps augmenting the magnetic attraction effect on said aperture.

9. An electromagnetic structure, as claimed in claim 8, in which said other yoke leg has lugs extending laterally from opposite side edges thereof and each aligned with the free end of a respective one of said armature arms; said last-named air gaps being formed between said lugs and the free ends of the associated armature arms.

10. An electromagnetic structure, as claimed in claim 8, in which said armature arms are adjustable relative to said other yoke leg.

11. An electromagnetic structure, as claimed in claim 4, in which said armature has a pair of laterally spaced arms extending substantially parallel to said core adjacent opposite sides of said third leg and forming, with said third leg, air gaps augmenting the magnetic attraction effective on said armature.

12, electromagnetic structure, as claimed in claim 111, in which said third leg has lateral lugs extending from each side edge thereof and each aligned with the free end of a respective one of said armature arms; said lastnamed =air gaps being formed between said lugs and the free ends of the associated armature arms.

13. An electromagnetic structure, as claimed in claim 11, in which said armature arms are adjustable relative to said third leg.

14. An electromagnetic structure, as claimed in claim 11, including a Winding on said core; said armature arms being disposed between the plane of the outer surface of said third yoke leg and said winding.

'15. An electromagnetic structure, as claimed in claim 14, including contact mechanism disposed outwardly of the plane of the outer surface of said third leg; and contact mechanism operating means engaged with the outer surfaces of said armature arms.

16. An electromagnetic structure, as claimed in claim 11, in which the outer surfaces of said armature arms, adjacent the free ends thereof, are outwardly of the plane of the outer surface of said third leg in the energized position of said armature.

17. An electromagnetic structure, as claimed in claim 4, in which said third leg serves as a mounting support for said electromagnetic structure.

BERNARD A. GILHEANY, Primary Examiner. G. HARRIS, Assistant Examiner. 

1. AN ELECTROMAGNETIC STRUCTURE COMPRISING, IN COMBINATION, A PARAMAGNETIC MATERIAL YOKE; A PARAMAGNETIC MATERIAL CORE IN MAGNETIC CIRCUIT WITH SAID YOKE; SAID YOKE HAVING LEG MEANS EXTENDING FROM ONE POLE OF SAID CORE IN SPACED PARALLEL RELATION TO SAID CORE AND TERMINATING IN THE PLANE OF THE OPPOSITE POLE OF SAID CORE IN LATERALLY SPACED RELATION WITH SAID POLE; AND A PARAMAGNETIC MATERIAL ARMATURE OSCILLATABLY SUPPORTED AT SAID LEG MEANS AND FORMING, WITH SAID OPPOSITE POLE OF SAID CORE AND WITH SAID LEG MEANS, FIRST AND SECOND AIR GAPS; SAID ARMATURE HAVING AN ARM EXTENDING SUBSTANTIALLY PARALLEL TO SAID CORE AND HAVING A FREE END FORMING, WITH SAID LEG MEANS, AN AIR GAP AUGMENTING THE MAGNETIC ATTRACTION EFFECT ON SAID ARMATURE. 